EXPLORING THE EFFECT OF TRANSCRANIAL DIRECT CURRENT STIMULATION ON UPPER-LIMB FUNCTION IN STROKE PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

L. Alabdulaali¹, L. Hickman¹, T.D. Punt¹, N. Jenkinson¹

¹University of Birmingham, Birmingham, United Kingdom

Background: Upper limb motor function is an important factor in many activities of daily living. Stroke patients suffer from limitation in upper limb function that reduces their independence and quality of life. Specifically losing dexterity of upper limb movement affects the ability to carry out skilful movements, e.g. dressing and eating.The recovery of upper limb motor function post-stroke is an important issue for stroke rehabilitation community. Transcranial direct current stimulation (tDCS) is a promising intervention to enhance upper limb motor function. However, the effect of the tDCS has been varied between studies.

Purpose: This study was conducted to investigate the difference effect of tDCS stimulating the primary motor cortex in the recovery of distal and proximal upper limb segments. Specifically, this study aimed to answer our research question “what (if any) is the difference in the effect of tDCS stimulation of the primary motor cortex between fine and gross dexterity of stroke patients with upper limb hemiparesis?”

Methods: This is a systematic review and meta-analysis conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols guidelines. The databases were searched for randomised controlled trial examining the effect of tDCS in improving dexterity of stroke patients.The following databases were searched for published studies: MEDLINE, SCOPUS, CENTRA, CINAHL, EMBASE and Web of Science. The following grey literature databases were searched for unpublished studies: ProQuest Dissertations and Theses and EThOS. The outcomes of interest were fine and gross dexterity measures.

Results: Eighteen studies met the inclusion criteria, involving 668 stroke patients. Ten studies have an excellent quality, and 8 studies have a good quality according to PEDro scale.The highest per cent of studies showed a low risk of bias by 50%, 45% had some concerns and 5% showed a high risk of bias according to Cochrane Collaboration’s Risk of Bias Tool. The results of 11 studies were included in the meta-analyses. The meta-analyses found a large significant effect of the tDCS on improving fine dexterity (SMD = 1.06; p = 0.001) and small non-significant effect on improving gross dexterity (SMD = 0.03; p = 0.77). The sub-group analyses showed that tDCS yields a significant benefit in chronic stage and a non-significant effect in subacute and acute stages.The overall certainty of evidence was moderate for fine and gross dexterity measures according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

Conclusions: The current systematic review and meta-analysis provide evidence that tDCS stimulating the primary motor cortex could enhance the fine hand movements that required skilful movements of the fingertips more than gross hand movement. The findings of this study need to be further explored in a large randomised controlled trial.

Implications: Given the differentiation in motor control of different upper limb segments, we recommend stratifying the upper limb movements in the assessment and the treatment into fine and gross dexterous tasks.

Funding acknowledgements: Imam Abdulrahman Bin Faisal University, Saudi Arabia.

Keywords:
Stroke
Dexterity
Rehabilitation

Topics:
Neurology: stroke
Disability & rehabilitation

Did this work require ethics approval? No

Reason: Ethical approval is not required for this type of study.